Electrophotographic material



United States Patent 11 Claims. for. 96-11) By the termelectrophotography are understood reproducing or recording processes inwhich latent electric charge patterns are developed. conventionally, theelectrophotographic material is in the form of a backing to which aphotoconductive layer is applied, with or without the interposition ofauxiliary layers and/ or electrical bar'- rier layers. Thephot-oconductive layer is very photosensitive when charged electrically.If the charged electrophotographic material is exposed, a latent chargepattern is produced, the electrostatic charge being reduced oreliminated at those parts of the electrophotographic layer which havebeen exposed to the light or radiation but remaining at non-irradiatedparts. The latent charge pattern can be developed by means ofappropriate liquid or solid triboelectric developer systems.

The photosensitive photocondu-ctive layer of this electrophotographicmaterial is produced by using special substances which can be calledphotoconductors without any limitation as to the mechanism of theiraction. A very wide variety of organic and inorganic substances havebeen proposed as photoconductors for use in electrophotographic layers,such as oxides, sulphides, selenides or arsenides of zinc, lead,cadmium, antimony, tin, and arsenic sulphide, lead chloride, sulphur,anthracene and pyrazoline derivatives, according to Federal Germanpatent specification 1,060,714, 1,3,4-triazole substances according toFederal German patent specification 1,060,260, azomethines according toFederal German patent specification 1,060,712, and poly-nuclear aromaticcompounds according to Federal German patent specification 1,060,- 259.To produce the electrophotographic layer, these photoconductors are usedin combination with a bonding agent of an insulating nature with orwithout an addition of substances which increase the water-repellantcharacter of the whole. However, nothing so far can be gathe'red fromthe large number of such different substances which enables accuratestatements to be made about the construction of such organic compoundsas can be used as photoconductors.

It has surprisingly been found that very useful and surprisinglyeffective electrophotographic materials can be prepared ifphotoconductors in accordance with the general Formulae I, II and IIIare used:

III.

where Ar and Ar denote an aromatic or heterocyclic cyclic system havingfree electron pairs, such as, for instance, benzene, naphthalene,diphenyl, anthracene, anthraquinone, polynuclear organic cyclic systemssuch as chrysene, perylene, fluorene or the like or pyridine, thiophene,coumarone, acridine, quinoline, imidazole, pyrazole, indole, pyrimidineor the like; X denotes one or more substituents adhering to the aromaticor heterocyclic ring system, such as H, halogen,

, phenyl, allyl, ethylene which can comprise other substituents, such as-OH, NH OR, NHR, Cl, CN, -SH, COOH, COOR or the like; Y denotes anoxygen or sulphur atom; Ac denotes an acid radical,

preferably that of an organic carboxylic acid, such as formyl, acetyl,or benzoyl, it being possible for dior poly-carboxylic acids, such asmalonic acid, oxalic acid, maleic acid, succinic acid, adipic acid,phthalic acid or terephthalic acid, trimesic acid, tartaric acid, citricacid or their substitution products to be reacted repeatedly withsubstances having the general Formulae L111; 11 denotes a whole numberfrom 2 to 3; and n denotes a whole number from 1 to 3. I

The Ar and Ar grouping and the X substituents can be so disposed thatsymmetrical and asymmetrical compounds are produced which can comprisethe X substituents in different ways and a number of times. Ar and Ar,"

may or may not belong to the same cyclic system. Symmetric andasymmetric compounds are suitable as electrophotographically activesubstances. The introduction of the prepare ketones having the generalFormula I and com:

prising a dialkyl amino group on the cyclic system, the analides of anaromatic or heterocyclic carboxylic acid, which may or may not becorrespondingly substituted, are

used as starting material and are reacted, using condensa-- tion agents,more particularly phosphoroxychloride, with tertiary aromatic amineshaving a free p-position and the reaction product is broken down withacids to the ketone. Appropriate tertiary amines are, for instance,dimethyl aniline, dicthylaniline, ethyl-(B-ox'yethyl)aniline,phenylmorpholine, ethyl-(B-acet-oxyethyl)aniline,u-dimethylaminonaphthaline, phenylpiperidine N acetate, N-methyl-diphenylamine and so on.

Substances having the general Formula II are, of course, prepared bycondensation of aromatic or heterocyclic methyl ketones with unsaturatedaldehydes. Substances having formula III are prepared eitherin the caseof symmetrical compoundsby condensation of 2 mol of the aldehyde with 1mol of acetone, with the action of alkaline or acid condensation agents,orin the case of asymmetrical compounds-by condensation ofstyrylmethyl-ketones and aldehydes. When X substituents are used whichcan react with the aldehyde, such substituents are, with advantage,masked before the reaction is performed. 7

Of particular value in the preparation of self-adhesive photoconductorsare those compounds having the general Formulae I-III which contain oneor more substituents reactable with epoxy and/ or isocyanate groups,possibly at diiferent reaction rates, and which contain reactablehydrogen one or more times in the molecule, possibly besides othersubstituents or sticking to the R substituent, as, for instance, in theOH, SH, NH NHR, COOH, CONH CONHR, SO NH SO NHR, -NI-ICONH =CH or =0, :8and -NO. These photoconductors which correspond to the general FormulaeI-III and which are reactable with epoxies or isocyanates are reacted,to produce self-adhesive photoconductors, with isocyanate-and/orepoxygroup-containing compounds, with or without an addition of otherparticipants in the condensation which are not photoconductors, toprovide electrophotographically active resin-like substances with markedadhesion on metals, ceramic products, papers, plastics, glasses andfabric materials. The following compounds were prepared in accordancewith the general Formulae I-III, the number denoting the structuralformula:

( 1 Tetramethyl-4,4-diamino-benzophenone (2)Tetramethyl-4,4'-diaminothiobenzophenone (3N",N""-tetramethyl-di-a'-amino-di-,B-pyridy1- thioketone (4)4,4'-dimethyl-diamino-3,3'-dimethylthiobenzophenone (5dimethyl-4amino-thiobenzophenone (6) 4,4'-dimethoxy-thiobenzophenone (74-dimethylamino-4'-nitro-benzophenone (84-dimethylamino-4'-amino-benzophenone (9) 4,4-dimethoxy-benzophenone(10) 4-dimethylamino-4'-chlorobenzophenone 11) Phenyl-a-thienyl-ketone(12) 4-dimethylamino-a-naphthyl-4'-nitrophenylketone 13)4-dimethylamino-a-naphthyl-4'-aminophenylketone 14) 4-N-ethyl-(fi-oxyethyl amino-benzophenone 15) di- (quinolyl)-(6)-ketone 16)4-dirnethylarnino-4-methylanilino-benzophenone 17)3nitro-4,4'-bis-dimethylaminobenzophenone 18)3-amino-4,4-bis-dimethylamino-benzophenone 19)4-dimethylamino-3'-nitro-benzophenone (20)2-oxy-4-diethylamino-benzophenonecarboxylic acid- (2) (212-oxy-4-diethyl amino benzophenone-carb oxylic acid-(2)-methyl-ester(22) 4-dimethylaminophenyl-3'-oxynaphthyl-2'-ketone (23 4-[methylfi-hydroxyethyl) amino] -cinnamal-4'- diphenyl-acetophenone (24)4-[methyl-(B-hydroxyethyD-amino] -cinnamal-3- nitro-acetophenone (254-dimethylamino-cinnamal-3 '-aminoacetophenone (26) 4-[methyl-(fl-hydroxyethyD-amino] cinnamal-2'-hydroxy-4'-dimethylamino-acetophenone (27)4,4'-bis-dimethylaminodibenzylidene-acetone (282,2-bisfi-methylamino-ethy-l )-benzal 29) Phenyl-(l-amino-anthraquinolyl) (2) ketone (30) 9-hydroxy-4-benzoyl fluorene (31 a-anisylidene-a- 3-nitro-cinnamylidene acetone (32)(4-dimethylamino-phenyl)-4-methylaminonaphthyl-( 1' ketone (33)u-(4-[methyl-(fl-hydroxyethyl)-amino]-cinnamylidene)-a'-(4-nitro-toluylene)acetone(34) 3 ,5 dinitro-4-diethylaminobenzophenone 35 4- [methyl-,B-hydroxyethyl) amino] -cinnamalacetyl-acenaphthene (36)2,2'-carboXy-benzoyl-7-dimethylaminofluorenone (37) 2- [2'-(carboxy-mono-glycol ester) benzoyl] 7- diethyl-amino-fluorenone (3 8)X,x-[bis-dimethylamino-1bis-p-diphenyl-ketone (3 9)1,1-carbonyl-di-indazole (40) 1- 4-nitrobenzoyl) indazole (41 1-4'-dimethylaminobenzoyl) 6-nitro-indazole 42) 1-(4-dimethylaminobenzoyl) -3- (4"-dimethylamino-phenyl) indazole (43) l-(4-diethylaminobenzoyl) 6-nitro-benzimidazole 44) 1- 2-carboxy-phenyl)benzimidazole (45 2- 4"-diethylaminobenzoyl 3 hydroxy-diphenyl 46) 2-4"-diethylaminobenzoyl) -3-hydroxy-4'- diethylamino-diphenyl.

The photoconductors according to the invention differ in their spectralsensitivity. For instance, Compound 22 is sensitive only to the spectrumof incandescent light, While with others it is convenient to addsensitisers to adapt the photoconductive layer to the spectral range ofdesired light sources. As a rule, this increases the photosensitivity.As sensitisers there can be used, for instance, the sensitisersconventional in silver halide photography. They can be used in aproportion of from 0.2 to 3% referred to the compounds having thegeneral Formulae I-III. For instance, the sensitisers disclosed byFrench patent specification 1,288,292 are suitable.

To produce the photoconductive layers, the photoconductors, whichcorrespond to the general Formulae I-III and which comprise Xsubstituents and which can react with epoxies and/or isocyanates, moreparticularly such photoconductors as have active hydrogen atoms, are,after reaction with isocyanates and/or epoxies, reacted to formself-adhesive photoconductors. Highly photosensitive photoconductivelayers can be prepared from these selfadhesive photoconductors withoutthe use of bonding agents. Such layers do not have any of the grainstructure of the photoconductor. Photoconductive layers can also theprepared by compounds corresponding to the general Formulae I-III or theself-adhesive photoconductors prepared from such compounds being used ina mixture or in solutions with bonding agents. Other photoconductors,such as zinc oxide, can be added. The bonding agents can be natural andsynthetic resins, with or without an addition of plasticisers. A numberof bonding agents are disclosed in French patent specification1,288,392. The bonding agents can either be dissolved in solvents orused as aqueous dispersions, depending upon their properties, incombination with one or more electrophotographically active compounds ofthe general Formulae I-IH, with or without an addition of sensitisingdyes, to produce the photoconductive layer. Bonding agents which incombination with solvents dissolve the photoconductors are convenient.

The proportion of electrophotographically active substancescorresponding to Formulae I-III to bonding agents can vary Within widelimits, and the charging time and photosensitivity can be varied by suchproportion being varied; the same can also be used to control theability to store latent electrostatic charge patterns fora prolongedtime.

The photosensitivity of the photoconductive layer also depends upon itsthickness. A thickness of from 0.002 to 0.1 mm., more particularly from0.004 to 0.008 mm., is very satisfactory. Above a critical thickness ofthe layer or emulsion, the image is reversed from positive to negative.This eifect is technically useful for the preparation of reversalmaterial.

To produce electrophotographic material, the preparation which forms thephotoconductive layer is applied to an appropriate backing material bysome form of conventional treatment, such as lacquering, centrifuging,spraying, electrostatic spraying, printing, coating with coating rollersand scraping oft with doctor devices, dipping, reeling, pressing withgrooved dyes, or in the form of a foil, with subsequent lining, or bymeans of an extruder. If required, the preparation can be embedded inthe form of a thin continuous layer in the backing material.

A very wide variety of substances, preferably in some sort of flat form,can be used as backing material for electr-ophotographic materials.Backing materials which are not so conductive electrically as is thephotoconductive layer are very useful. In particular, metal plates orfoils, including those which have undergone changes in surfacecomposition by electrical or chemical treatment, papers, fabric fleeces,electrically conductive plastics and foils, electrically conductiveceramic products and so on have proved satisfactory ,as backingmaterials. Papers or foils which have been vapour coated with metals,supports which have been connected to metal foils, papers or fibrefleeces which have been rendered conductive by an addition ofelectrolytes or of moisture stabilisers, or such supports as haveelectron-conductive substances, such as powdered metal, carbon black orgraphite embedded in them, are particularly suitable. Also suitable areplastics containing metals or metal compounds, carbon or a largeproportion of electrolyte. Non-conductive backings can be provided witha conductive layer of lacquer on their surface. A very wide variety ofcombinations is therefore possible.

Uniformity in the thickness of the photoconductive emulsion has a verygreat effect on the quality of the finished image. Advantageously,therefore, backings having a non-uniform surface are provided with anauxiliary layer which forms a smooth and closed surface. This auxiliaryor intermediate layer can be so devised as, if required, to increase andequ-alise the conductivity of the backing material and to improve theadhesion and anchorage of the electrophotographic layer on the backing.Preferably, the substances used for the intermediate layer aresubstances which are dissolved or changed little, if at all, by thepreparation which leads to the electrophotographic layer. Organicwater-soluble colloids have proved very useful for these purposes. Suchsubstances are, for instance, cellulose ethers, such as methylcelluloses and cellulose glycol acids, including those which have beenpartly reacted with ethylene oxide or propylene oxide, starch ethers,casein, polyuronides, the salts or amides thereof, ethylene or propyleneoxide reaction products, natural colloids, such as Irish moss, starches,including broken-down starches, gelatin, lichenin, agar-agar,tragacanth, hydrate celluloses, .and synthetic resins, such as polyvinylalcohol, polymethacrylic acid and its acetals, methyl hydantoin resins,maleinate-polyacrylic acid resins or others which contain free carboxylgroups and are Water-soluble in their salt form. A further increase inthe electrical conductivity of the emulsions can be provided by anaddition of soots, metal powders or electrolytes and moisturestabilisers, such as sorbitol, polyglycol ethers, broken-down starchesor hygroscopic metal salts.

Photoconductive emulsions prepared by the process according to theinvention are also of use in the preparation of printing plates such asare used, for instance, for offset printing. For this purpose, thephotoconductive layer is produced from compounds having the generalFormulae I-III, preferably in their form as self-adhesivephotoconductors, possibly in combination with bonding agents or otherphotoconductors, such as zinc oxide. Particu larly goodelectrophotographic emulsions for printing can be prepared from theself-adhesive photoconductor type reaction products of those compoundsaccording to Formulae I-III comprising substituents which can react withisocyanates and/or epoxies to form resin-like substances. The solubilityof the electrophotographic emulsions can be varied within wide limits byusing appropriate compounds which contain isocyanate and/or epoxy groupsand by reaction with other substances which are not photoconductors.

To this end, pretreated papers, plastic foils or fabrics,

or possibly a colloidal or resin emulsion in the form of a combinationor selection of gum arabic, caseinates, polyuronide salts, moreparticularly their zinc salts, dextrines, starches, starch ethers,polyvinyl alcohols including those containing acetate or acetal groups,agar-agar, z-inc salts of resin or fatty acids, polyacrylates orpolymethacrylates, amides of polyacrylic acids, cellulose ethers andgelatin, are applied to a backing which has been pretreated to make itsuitable for printing purposes, such as metal foils which have beengalvanically treated by oxidation, for instance, by eloxation or byaloidinisation or which have a very finely roughened surface. Thepreparation forming the photoconductive layer is applied by appropriateapplicators, preferably mechanically, to this backing material which hasbeen pretreated to make it stick and/or to make it take up water orwhich has been provided with hydrophilic intermediate layers, whereafterthe photoconductive layer or emulsion is dried. The electrophotographicemulsion should be such that the self-adhesive photoconductors, usingcompounds having the general Formulae IIII, or theelectrophotographically active substances having the general FormulaeI-III and also the bonding agent are soluble in conventional solvents orin water, whereas the toner used to produce the image must not beattacked. by the same solvents.

Conveniently, the bonding agent is hydrophilic, so that thenon-de-emulsified developed printing plate can be used for printingimmediately after wetting.

The process for preparing printing platescan also be used, of course, toprepare etched engravings, for instance, in the preparation ofimpression rollers or stereo blocks, and in the preparation of printedcircuits. The toner, in a form resistant to .acid and in a fused-instate, then serves as masking agent, while the photoconductive layer notrequired for image production is removed before etching by conventionaletching agents, preferably from the metallic support.

Example 1 20 g. of phenyl-ot-thienyl-ketone in accordance with Formula11 are dissolved with slight heating in cc. of ethyl acetate, and thereis added to this mixture a solution of 40 g. of a copolymer of vinylchloride and vinyl acetate (commercial product known as Vinylite VAGH)in 30 cc. of ethyl acetate and 50 cc. of butyl acetate. To produce thephotoconductive emulsion, the solution just described is applied in acentrifuge to an electrochemically polished and eloxated aluminium foil.The colourless electrophotographic plate is charged to -7 kv. under acorona discharge type electrode arrangement, the positive electrodebeing formed as a baseplate on which the electrophotographic material issupported. The negative electrode is in the form of thin tungsten wireswhich are from about 0.02 to 0.1 mm. thick and which are at a distanceof from 10 to 15 mm. from the electrophotographic plate and at adistance of 15 mm. from one another. This arrangement is conventionallyused to charge the electrophotographic material. If the tungsten wiresare made positive in the baseplate negative, the electrophotographicplate is charged positively. The charged electrophotographic material isexposed below an original with a high-pressure mercury vapour lamp for20 seconds, then developed by means of a tribo electric systemcomprising a toner and glass balls, the toner being made of plastics,colouring agents and/or soots. If the toner known commercially as theGraph-O- Fax-Toner No. 39/50, of the P. A. Hunt Company, and glass ballsare used, a positive original gives a positive image which can be fixedby being heated to C. or by the action of solvent vapours.

The electrophotographic material can be used for image transfer in anelectric field to other, preferably sheet-like substances, such aspaper, plastics foil or the like. Ade- .qua-te sensitivity for workingwith incandescent light can tising colouring agents to the coatingsolution, referred to the photoconductor, such as Rhodamin B(Schultz-Earhstofitabellen, Leipzig 1931, No. 864) or brilliant green(Schultz-Farbstotftabellen, Leipzig 1931, No. 760).

Example 2 2 g. of 4-dimethylamino-4'-aminobenzophenone in accordancewith Formula 8 are dissolved in l cc. of methylethyl ketone and 10 cc.of dimethyl formamide and added to a solution consisting of 4 g. of acolophonymaleic acid resin, for instance, the commercial product knownas Alresat 3l3c, and l g. of ethyl cellulose, for instance, thecommercial product known as ethyl cellulose N200, dissolved in 40 cc. ofaceto-ethyl. A thin coating of this solution is applied to a pretreatedpaper support which cannot be penetrated by the emulsion solution andwhich has been made icnically conductive by impregnation. Afterevaporation of the solvents a slightly yellowish electrophotographicmaterial is yielded on which images can be produced directly. To thisend, the material is charge-d up to -8 kv. as described in Example 1,placed below a positive original and expose-d to ultra-violetfluorescent tribes. When the material is developed with a soot-stainedresin powder and glass balls or iron filings in association with amagnet, a high-contrast positive image is produced at the unexposedplaces and is fixed by slight heating and/or solvent vapours. Anaddition of Rhodamin B and Pinacyanol blue is useful to increase thesensitivity to incandescent light.

Example 3 g. of 4-dimethylarnino-4-nitro-benzophenone in accordance withFormula 7, and 11 g. of a ketone or ketonealdehyde resin, ifOI instance,the synthetic resin commercially known as A P, are dissolved in 100 cc.of methyl ethyl ketone and 25 cc. of dimethyl formamide with heating andused to coat an aluminium plate in a centrifuge. After removal of thesolvents, the applied layer sticks tightly to the support. Thiselectrophotographic material is used to produce an image in the mannerdescribed in Example 1. The produced and still unfixed and, forinstance, positively charged powder image is covered with a sheet ofpaper, with a waxed paper or with resin-impregnated paper or with aplastics foil and is so introduced into an electric field produced by avoltage of from 2 to 6 kv. at a spacing of 20 mm. that the negativeelectrode is associated with the back of the sheet of paper. The, forinstance, positively charged toner is therefore transferred to the sheetmaterial in laterally inverted ztorm and can be fixed by heating and/orsolvent vapours. Contact copies on a transparent material can be used asintermediate originals for other photocopies, for instance, photoprints,for projection purposes and so on.

Example 4 '31 g. of 2-oxy-4-diethylaminobenzophenone-carboxylic acid (2)according to Formula 20, and 0.3 g. of Rhodamin B, are dissolved withheating in 100 cc. of cyclohexanone. There are added to the cooledsolution 47 g. of a reaction product which contains three freeisocyanate groups in the molecule and which has been prepared from 1 molof 1- trimethylol pnopane and 3 mol of toluylene-2,4-diisocyanate and/or toluylene-Z,6-diisocyanate (commercial product known under the trademark of Desmodur L), 75% by weight in an ethyl acetate, dissolved in 100cc. of cyclohexanone. The mixture is condensed at 151 C. with refluxboiling lfOI 20 minutes, the viscosity increasing considerably. Thecondensation gives the reaction product dissolved in cyclohexanonelimited compatibility with acetone. If the reaction product is mixedwith acetone in the proportion of 1, the self-adhesive photoconductorseparates out. The reaction should be so controlled that nothreeadimensional cross-linking occurs. 25 g. of the reaction solutionare mixed with 25 cc. of methyl ethyl ketone and 35 cc. of dioxane and,after filtration, used to prepare the electrophotographic layer, anelectrochemically polished aluminium foil being so coated in a centri-(fuge that a layer thickness of about 0.006 mm. dry is produced. Thecoated plate is dried by ultra-red radiation on the centrifuge, thenbaked at 130 C. for 5 minutes. A lustrous very strongelectrophotognaphic layer which sticks fast mechanically to the backingis produced. It is charged electrostatically at 7 k v. for 3 seconds,exposed below an original with ultra-violet fluorescent tubes for 1second, then developed using glass balls and a direct toner. Ahigh-contrast electrophotographic image is produced.

Another method of producing an image is for the electrophotographicplate just described to be exposed when charged through a microfilm, andfor a time of 25 seconds, in an enlarger having a 150 Wattcine-projection lamp, with an aperture ratio of 1:5.6 with a distance of30 cm. between the lens and the plate. A high-contrastelectrophotographic image is yielded after development.

The still unfixed electrophotographic recordings can be transferred inan electric field to other substances, preferably in sheet form, asdescribed in Example 1.

Example 5 145 g. of 4-N-ethyl-(fi-oxyetbyl)-aminobenzophenone accordingto Formula 14 are reacted with 300 g. of ethylene glycol diglyoide etherat 170 C. in a nitrogen atmosphere for 30 minutes, whereafter 190 g. ofethylene glycol diglycide ether boiling at from 142-167" C./ 3 torr. aredistilled oil in a vacuum produced by an oil pump. The resin whichremains as residue is dissolved hot in 500 cc. of cyclohexanone and tothis solution there are added 200 g. :of a modified isocyanate (thecommercial product called Desmodur L) in a proportion of 75 by weight inethyl acetate, and condensation is eifected at C. (usually for 5minutes) until the solution is still compatible with methyl ethyl ketoneand no gelatinisation occurs. 100 cc. of the cooled reaction solutionthus prepared are diluted with 200 cc. of methyl ethyl ketone. Thissolution is applied in a uniform thickness of 0.008 mm. to a highlylustrous aluminium foil. The photoconductive layer formed is dried in anair stream first at C. and then for a short time at C. Theelectrophotognaphic material formed, when charged as set forth inExample 1 to 7 kv. and exposed under a positive original with ahighpressure mercury vapour lamp or a pulse discharge tube, yields upondevelopment a high-contrast positive reproduction which can also be usedfor image transfer.

Example 6 77 g. of 4-dimethylamino-4-amino-benzophenone according toFormula 8 are dissolved in 300 cc. of cyclohexanone, 88 g. of a modifiedtriisocy-anate (commercial product called Desmodur L) in a proportion of75 by weight in ethyl acetate, dissolved in 200 cc. of cyclohexanone,are added and condensing with reflux boiling is effected at from to 152C. for 30 minutes. To prepare the electrophotographic material, aplastics-impregnated smooth-surfaced glass fibre fleece which has hadaluminium vapour coated onto it smooth side is used as backing material.A solution consisting of 50 cc. of the reaction product just describeddiluted with 100 cc. of methyl ethyl ketone and 0.3 g. of erythrosine(corresponding to the Schultz-Farbstofftabellen 1931, No. 886) .and 0.2g. of brilliant green (corresponding to the Schultz-Farbstofitabellen1931, No. 760) are applied to the backing material in a centrifuge,dried with ultra-red radiation and baked at 120 C. A flexible firmlyadhering electrophotographic layer having considerable abrasionresistance is produced and can be used as set forth in Example 1 in thepreparation of electrophotographic reproductions. Theelectrophotographic material is very sensitive to incandescent light.

Example 7 105 g. of 4-[methyl-(fi-hydroxyethyl)-arnino]-cinnam \al 2'hydroxy 4 dimethylamino-acetophenone corresponding to Formula 26 aredissolved in 300 cc. of cyclohexanone, and 88 g. of a modifiedtriisocyanate (commercial product called Desmodur L), in a proportion of75% by weight in ethyl acetate, are added and reacted at 150 C. for 20minutes. 100 cc. of the reaction solution are mixed with 50 cc. ofmethyl ethyl ketone and with 50 cc. of ethyl amyl ketone and paintedonto an aluminium foil which is dried in an air stream at 120 C. Theelectrophotographic material is charged up to 6 kv. and exposed under apositive original with a high-pressure mercury vapour lamp or an arclamp or ultra-violet fluorescent tubes. Using a toner having a particlesize of from to 50 1.1. and glass balls, a high-contrast positive imageof the original is produced which can be fixed by heating and/ orsolvent vapours.

To transfer the image to other fiat materials, such as papers orplastics foils, the unfixed image on the electrophotographic plate isbrought into intimate contact with sheet material and so introduced intoan electric field that, for instance, the negative electrode is disposedbehind the sheet material. If the electric field is strong enough, forinstance, of 6 kv./ 20 mm., printing is elfected by the field strengthalone. By intermediate changes of a field of differing field strengthand direction, varying quantities of toner can be. transferred and anumber of copies can be prepared from one image on theelectrophotographic plate. The transfer image is fixed like theelectrophotographic plate.

Example 8 28 g. of 4-dimethylamino-tcin=namal-'3 aminoacetophe.

none in accordance with Formula 25 are prepared fresh, introduced into asolution consisting of 50 g. of an epoxy resin of the type formed bydiphenol propane which has been reacted with epichlorohydrin and whichhas been partly condensed with itself with molecule enlargement(commercial product known as Epikote 1001 Shell), in 250 cc. of ethylamyl ketone, and dissolved with heating and agitation. The solution iskept at about 100 C. with reflux boiling for 20 minutes, its viscosityincreasing considerably. 100 cc. of reaction product are diluted with 50cc. of methyl isobutyl ketone and 50 cc. of methyl ethyl ketone, and tothis are added, to produce a non-sticky surface, 5 g. of a modifiedtriisocyanate (commercial product called Desmodur L), 75% by weight inethylacetate, and 0.2 g. of Rhodamin B as per Schultz-Farbstofitabellen1931, vol. 1, No. 864 and 0.1 g. of pinacyanol as per SchultzFarbstolftabellen 1931, vol. 1, No. 924, then used immediately toproduce the electrophotographic layer.

The backing material is a copper foil which has a smooth front but aspongy back and which is connected on the back to a resilienthigh-melting plastic or to rubber. The dissolved self-adhesivephotoconductor is applied to the front of this backing material anddried in an air stream at 100 C. to remove the solvents, whereafter thefront is given a brief radiant heat treatment at 120 C.

Example 9 diisocyanate in 300 cc. of cyclohexanone at 148 C. for 3hours. Small traces of toluylene-2,4-(or 2,6) diisocyanate are removedfrom the solvent-free reaction product by molecular distillation. Thereaction product contains about 17% by weight of free isocyanate groups.This solution of self-adhesive photoconductor is applied by applicatorcomprising dispensing rollers onto an aluminium-vapour-coated cellulosepaper having a density of g./m. dried in a Warm air stream, then givenbrief afterheating at C.

Because of its green colour, the self-adhesive photoconductor is veryphotosensitive. When charged up in a coronary discharge arrangement to-7 kv., then exposed below a positive original with ultra-violet coldlight tubes for 3 seconds, the substance, after development with glasspowder and a direct toner, provides a high-contrast positive image whichis fixed by heating or by solvent vapours.

Another generally applicable development method is the use of so-calledliquid developers comprising a dispersion of dye particles with anaddition of soluble or dispsersed plastics in a liquid medium. With thismethod, similarly to the development by means of powdery developers ofelectrophotographic layers or emulsions prepared from self-adhesivephotoconductors, development can be effected if the liquid phase of thedeveloper is such that the electrophotographic emulsion is notdissolved. Preferably, the photoconductive emulsions prepared fromself-adhesive photoconductors are of the kind which still containreactable isocyanate and/or epoxy groups and are given three-dimensionalcross-linking during the production of the electrophotographic emulsion.To this end, small quantities of polyamines, polycarboxylic acids orpolyalcohols are added to the preparation which will subsequently leadto the electrophotographic layer, and cross-linking is effected duringdrying by the use of heat.

Example 10 15 g. of a chlorinated diphenyl resin, for instance, thecommercial product called Clophenharz W, and 3 g. of a broken-downnatural rubber, for instance, the commercial product known as Cyclosit,are heated to 150 C. to produce a homogeneous melt. 5 g. oftetramethyl-4,4'- diaminobenzophenone in accordance with formula 1 aredissolved in the melt, whereafter the same is used, at a temperature offrom to C., to coat heat-stable backing materials forelectrophotography, for instance, by the melt being applied to aluminiumsheet which has been heated to 140 C.

Emulsion thicknesses of from 0.005 to 0.01 mm. are very useful toprovide short exposure times and a substantially colourless emulsion.The electrophotographic material is charged up to 7 kv. and exposedbelow a positive original with ultra-violet fluorescent tubes for 15seconds. After development as set forth in Example 1, a high-contrastpositive electrophotographic image results which is fixed by heating orby solvent vapours or which can be used for transfer to other materialsin an electric field. High sensitivity to incandescent light can beprovided by an addition of 0.2 g. of Rose bengale (Schultz-Farbstoiftabellen 1931, No. 889) 0.05 g. of Pinaflavol(Schultz-Farbstoiftabellen 1931, No. 925 and 0.05 g. of Pinacyanol(Schultz-Farbstofitabellen 1931, No. 924).

As an alternative method of application, the electrophotographic layeris applied from the melt to the backing material by means of pressingtools which ensure a thin and uniform thickness of the emulsion. Thematerial is ready for use immediately after cooling.

Example 11 dissolved in 20 cc. of methyl ethyl ketone, are added.

To use this solution to coat backing materials on the centrifuge, 1 partby volume is diluted with 1 part by volume of methyl ethyl ketone andwith 2 parts by volume of cyclohexanone.

A 60 g./m. cellulose paper is coated with a preparation to inhibitpenetration of the electrophotographic layer and with aconductivity-promoting protective layer. The latter layer is prepared,for instance, by application of a solution consisting of:

3 g. of a film-forming methyl cellulose,

5 g. of ammonium chloride,

2 g. of zinc chloride,

5 g. of sorbitol, and

1 g. of 'boric acid dissolved in 100 g. of water,

and subsequent drying in an air stream at 100 C. The preparation leadingto the photoconductive layer is applied to the backing material whichhas been thus prepared, and is dried in a stream of warm air at 120 C.The electrophotographic material can be used for image production as setforth in Example 1. When the material is charged negatively, placedunder a positive original and exposed with a high-pressure mercuryvapour lamp and developed, a positive image is provided.

The preparation just described for the production of theelectrophotographic emulsion can also be used in the preparation ofprinting forms. To this end, it is applied to a backing material whichhas a hydrophilic surface, for instance, in the form of a colloidallayer, or which is in the form of an electrically or chemicallypretreated metal foil, and the whole is dried in a warm air stream. Theelectrophotographic material is ready for use after drying and can becleaned by being washed with Water and/or detergents. To prepare theprinting form, for instance, the electrophotographic plate is brieflycharged at 7 kv., then placed below a positive original and irradiatedwith short-wave light either by the direct contact method or with theinterposition of a microfilm in the projection method. From a positiveoriginal, a positive image is provided after development with a tonerwhich is insoluble in alcohol and is suitable more particularly toreceive printing ink, and with glass balls. To provide a firm anchorage,the toner is melted into the photoconductive layer. By removal of theemulsion with ethanol, the electrophotographic plate is converted into aprinting form, that area of the photoconductive emulsion which has notbeen used for the image being removed. The form, after being wiped overwith 30% phosphoric acid and possibly being given a further shortmelting-in treatment, is inked on an offset printing press with asimultaneous supply of water and printing ink. The form gives a largerun with exact reproduction of the print.

Example 12 87.5 g. of a modified triisocyanate, formed by reacting 3 molof 2,4-toluylene diisocyanate and 1 mol trimethylolpropane containingthree free isocyanate groups (for instance, the commercial productcalled Desmodur L), 75% by weight in ethylacetate, 28 g. of n-dodecanoland 57.5 g. of 4 [methyl(/3-hydroxyethyl)-amino]-cinnamal-4-diphenyl-acetophenone in accordancewith the Formula 23, are dissolved in 200 cc. of cyclohexanone andreacted at 140 C. to a self-adhesive photoconductor which is soluble incyclohexanone. The reaction product is diluted with 400 cc. of ethylamyl ketone, and 1 g. of Rhodamin 3 B (No. 867), 0.3 g. of Orthochrom T(No. 923), and 0.3 g. of naphthacyanol (No. 926) are added, the numberswhich follow the sensitisers referring to the SchultZ-Farbstolftabellen,vol. 1, 1931. To prepare the photoconductive emulsion, the solution justdescribed is so applied mechanically to a paper-lined aluminium foil,and so dried in a warm air stream at 125 C., that the thickness of theemulsion is from 0.005-002 mm. A firmly adhering highly photosensitivephotoconductive layer is produced.

The aluminium foil of the electrophotographic material is connected tothe positive side of the charging device and charged to a negativecorona of kv. The material is exposed, through a film bearing a positiveimage, in an enlarger comprising a 250-watt incandescent lamp at ansteps of the process.

aperture ratio of 1:45 and at a distance of 50 cm. between the lens andthe plane of the image, for 4 seconds, then developed by means of adirect-acting triboelectric system, for instance, the commercial productknown as Graph-O- F ax-Toner 39/50, and glass balls, and a high-contrastpositive image of the original is provided. The powder image can befixed by known steps, such as by being heated to 120 C.

If the photoconductive emulsion is charged with a positive corona of 10kv., exposed through a negative original and developed with a reversaltoner, for instance, the commercial product known as Xerox-Toner SCl3,and glass balls, a positive image of the negative original is provided.

Example I 3 10 g. of tetramethyl-4,4-diaminothiobenzophenone inaccordance with Formula 2, and 0.3 g. of Rhodamin 3 B, corresponding tothe Schultz-Farbstofitabellen 1931, No. 867, are dissolved in 40 g. of achlorinated diphenyl resin, for instance, the commercial product knownas Clophen Harz W, which has been heated to 120 C. This melt is used inthe preparation of electrophotographic material in the manner set forthin Example 10.

Example 14 30 g. of 4,4'-bis-dimethylamino-di-benzylidene acetone inaccordance with Formula 27, and 87.5 g. of the reaction product preparedfrom 3 mol of toluylene-2,4 (or 2,6)-diisocyanate and 1 mol oftrimethylolpropane (for instance, the commercial product known asDesmodur L), by weight in ethyl acetate, are dissolved hot in 150 cc. ofcyclohexanone and 300 cc. of 'ethylamyl ketone. A solution of 20 g. ofhexane-diol-l,6 in cc. of ethylamyl ketone is added, and this freshlyprepared solution is used to coat an aluminium foil to a thickness offrom 0.004 to 0.05 mm. The applied and still solvent-containingphotoconductive emulsion or layer is dried in a warm air stream andafter-heated at 140 C. for a further 5 minutes. A firmly adheringphotoconductive layer of a deep orange-reddish colour is produced whichis very sensitive to incandescent light and to longwave ultra-violetlight. The electrophotographic material is charged to -6 kv. for a shorttime, then exposed for 5 seconds through a microfilm in an enlargerhaving a 250 watt cineprojection lamp, through a lens having an apertureratio of 1:4.5, with a distance of 30 cm. between the lens and the planeof the image. After development with a triboel'ectric system using adirect toner and glass powder, a high-contrast positive electrographicimage of high resolution is produced. The picture thus prepared can beused for image transfer in an electric field or by pressing, forinstance, on paper or plastics foils. Fixing is by heating and/0rsolvent vapours.

Example 15 2 g. of 4,4'-dimethoxy-thiobenzophenone in accordance withFormula 6, 4 g. of a ketone or aldehyde resin, for instance, thesynthetic resin known commercially as AP, and l g. of 65% collodionwool, wetted with ethanol, are dissolved in 4 cc. of ethanol, 60 cc. ofacetone and 20 cc. of butyl acetate. The' solution is used to coat a 0.3mm. thick aluminium foil in a centrifuge, the coating being uniform,whereafter drying is effected in an air stream at C. Theelectrophotographic material has a high metallic lustre and a slightblue tinge. When the material is charged to 7 kv. and exposed with ahighpressure mercury vapour lamp below a positive original, ahigh-contrast positive electrophotographic image of high storagecapacity is produced.

It is usually possible, after removal of the powder image, rechargingand exposure below a dilferent original, to produce a secondelectrophotographic image on the same electrophotographic plate afterrepetition of the However, when the electrophoto- .13 graphic materialjust described is recharged to 7 kv. after removal of the first imageand is exposed to the same light source but without any original, theimage first produced is produced again after development. This latentelectrostatic image is very difficult to destroy just by alteration ofthe field direction during charging but can be expunged by heating to 80C. or by treatment with water or water vapour. This electrophotographicmaterial is suitable for storing latent electrostatic charge patterns.

Example 16 g. of 2-oxy-4-diethylamino-benzophenone-carboxylic acid(2)-methyl ester in accordance with Formula 21, 0.2 g. of Rhodamin B(Schultz-Forbstofftabellen No. 864), and 17.5 g. of a modifiedisocyanate having three reactable isocyanate groups in the molecule, forinstance, the commercial product known as Desmodur L, are dissolved in45 cc. of cyclohexanone and condensed with reflux boiling for 30minutes. The solution is cooled to room temperature, then 5.6 g. ofdi-(2-ethylh'exyl)-amine dissolved in cc. of cyclohexanone are added andthe mixture is reacted at 100 C. for 10 minutes.

The photoconductive emulsion produced from this selfadhesivephotoconductor is readily soluble in lower aliphatic alcohols and isvery sensitive to incandescent light. It is very useful for producingelectrophotographic material for use in printing forms, moreparticularly for offset printing. To this end, the solution ofself-adhesive photoconductor, preferably in a very dilute condition, isapplied to a print support and dried. As print supports there aresuitable papers which have'been pretreated with a colloidal emulsion,aluminium foils which- Example 17 43.75 g. of triisocyanate modified inaccordance with Example 12, 75 by weight in ethylacetate, and 32 g. of2,4-di-hydroxy benzophenone are dissolved in 100 cc. of cyclohexanoneand first reacted with reflux boiling at 150 C. for 10 minutes,whereafter the temperature is increased to 200 C., the cyclohexanonebeing distilled off. The light-yellow thickly viscous resin is dissolvedhot in 90 cc. of cyclohexanone.

1 part by volume of the solution of self-adhesive photoconductor isdiluted with 2 parts by volume of methyl ethyl ketone and so applied toa bright eloxated aluminium plate, to produce the photoconductiveemulsion, and dried, that the emulsion thickness is 0.01 mm. The hardsubstantially colourless photoconductive emulsion sticks satisfactorilyto the backing material and has a high storage capacity for the electriccharge. If the emulsion is charged with a negative corona to 10 kv. fora short time, placed below a positive original, irradiated withultra-violet fluorescent tubes for 10 seconds, then developed with atriboelectric developer comprising glass balls and the commercialproduct known as Graph-O-Fax-Toner 39/50, a high-contrast positive imageof the original 'with high resolution is produced.

100 g. of the self-adhesive photoconductor dissolved in cyclohexanoneare diluted with 50 g. of methyl ethyl ketone, 100 g. of Zinc oxide(makers name: Florence- Green No. 8) are added, and the mixture isground in a vibrating ball mill for 2 hours. The preparation, which canreadily be applied as a coating, is applied to 60 g./m. cellulose paperto produce the photoconductive layer and is dried in a warm air streamat 120 C.

When this material is charged under a negative corona of from 6-10 kv.,placed below a positive original, irradiated with ultra-violetfluorescent tubes for 0.04 sec ond, then developed with the toner justdescribed, a highcontrast positive image of the original is produced inwhich fine lines are reproduce-d and in which the resolution is high.The toner image can be developed by liquid developers or by toneraerosols. Fixing is effected by known steps, for instance, by heating toC.

What I claim is:

1. An electrophotogr-aphic material comprising a carrier and anelectrophotographic layer thereon, said layer containing a low molecularnon-polymeric ketone of the formula X and X are each selected from thegroup consisting of halogen, CN, NHg, NHR, NR OH, OR, SH, SR, COOH,COOR, -CONH CONR :0, =5, =SO, SO NH SO NHR, SO NR NO --NO and aliphaticresidues of 1 to 12 C-atoms;

and wherein R is selected from the group consisting of an aliphaticresidue of 1-l2 carbon atoms, phenyl, naphthyl, diphenyl, polarsubstituted phenyl, naphthyl, and diphenyl,

wherein the polar substituents are selected from the group consisting ofOH, SH, -NH NHCHg, NHC H Cl, -CN or COOH;

wherein Ar and Ar are each selected from the group consisting ofmononuclear rings having aromatic properties, two mononuclear ringshaving aromatic properties connected to one another by a single carbonatom, and two ortho condensed mononuclear rings having aromaticproperties, and wherein n is any whole number selected from 1, 2 and 3and n is whole numbers from Zero to 3.

2. The electrophotographic material of claim 1, wherein the lowmolecular, non-polymeric ketone is reacted with an organic isocyanate,whereby the reaction products are electrophotographically active andwhich firmly adhere to the carrier without the addition of a separatebinder, so as to form a self-adherent electrophotographic layer. I

3. An electrophotographic material comprising a carrier and anelectrophotographic layer thereon, said layer containing a lowmolecular, non-polymeric ketone of the formula X and X are each selectedfrom the group consisting of halogen, CN, --NH -NHR, NR OH, OR, -SH, SR,COOH, COOR, CONH -CONR2, 0, i, =SO, SO2NH2, SO NR N0 NO and aliphaticresidues of 1 to 12 C-atoms;

and wherein R is selected from the group consisting of an aliphaticresidue of 112carbon atoms, phenyl, naphthyl, di-v phenyl, polarsubstituted phenyl, naphthyl, and diphenyl,

wherein the polar substituents are selected from the group consisting ofOH, SH, -NH NHCH NHC H Cl, CN or COOH;

wherein Ar and Ar are each selected from the group consisting ofmononuclear rings having aromatic properties, two mononuclear ringshaving aromatic properties connected to one another by a single carbonatom, and two ortho condensed mononuclear rings having aromaticproperties, and wherein n is any whole number selected from the groupconsisting of 1, 2 and 3 and n is any integer from zero to 3.

4. The electrophotographic material of claim 3, wherein the lowmolecular, non-polymeric thioketone is reacted with an organicisocyanate, whereby the reaction products are electrophotographicallyactive and which firmly adhere to the carrier without the addition of aseparate binder, so as to form a self-adherent electrophotographiclayer.

5. An electrophotographic material comprising a carrier and anelectrophotographic layer thereon containing.

a low molecular weight nonpolymeric compound selected from the groupconsisting of ketones and thioketones having the formula t it.

group; and wherein Z is selected from the group consisting of O and S.

6. An electrophotographic material comprising a carrier and anelectrophotographic layer thereon containing a low molecular weightnon-polymeric compound selected from the group consisting of ketones andthioketones having the formula which is reacted with an organic epoxidecompound; and wherein X and X; are each selected from the groupconsisting of NHR, -NR OR, -SR, COOR, CONHR, CONR 'SO NHR, and 4O NRwherein R is selected from the group consisting of phenyl, naphthyl, anddiphenyl, each substituted by polar constituents selected from the groupconsisting of OH, -SH, NH -NHCH NHC H COOH, CN, and Cl; and wherein Yand Y are each selected from the group consisting of OH, SH, =NOH andCOOH each in an ortho position of the group; and wherein Z is selectedfrom sisting of O and S.

7. An electrophotographic material comprising a carrier and anelectrophotographic layer thereon containing a mixture of the reactionproduct of claim 5 and zinc oxide.

8. An electrophotographic material comprising a carrier and anelectrophotographic layer thereon containing a mixture of the reactionproduct of claim 6 and zinc oxide.

9. An electrophotographic material comprising a carrier and anelectrophotographic layer thereon containing the group con- 1e a lowmolecular weight nonpolymeric compound selected from the groupconsisting of ketones and thioketones having the formula wherein X and Xare each selected from the group consisting of halogen, CN, NH-Alkyl,N(Alkyl) -(Aryl) OH, O-Alkyl, -O-Aryl, SH, S-Alkyl, S-Aryl, COOH,COO-Alkyl, COO-Aryl, CONH CON(Alky1) COH(Ary1) =0, :5, =80, SO NH SONH-Alkyl, SO NH-Aryl, SO N(A1ky1)z, SO (Ary-l) NO Alkyl and Aryl; andwherein Z is selected from the group consisting of O and S; and whereinn is any whole number selected from the group consisting of 1, 2, and 3and n is any integer from Zero to 3.

10. An electrophotographic material comprising a carrier and anelectrophotographic layer thereon containing a low molecular weightnonpolymeric compound selected from the group consisting of ketones andthioketones having the formula wherein X and X are each selected fromthe group consisting of NHR, NR OR, SR, COOR, CONHR, CONR -SO NHR and SONR and wherein R is selected from the group consisting of phenyl,naphthyl, and diphenyl, each substituted by polar substituents selectedfrom the group consisting of OH, SH, NH NHCH -NHC H COOH, CN, and Cl,and wherein Z is selected from the group consisting of O and S; andwherein n is any whole number selected from the group consisting of 1, 2and 3 and n is any integer from zero to 3.

11. An electrophotographic material comprising a carrier and anelectrophotographic layer thereon containing a material selected fromthe group consisting of:

N",N""-tetramethyl-di-u-amino-di-B-pyridylthioketone,

phenyl-a-thienyl-ketone,

di-(quinolyl) (6 ketone,

4- [methyl- (,B-hydroxyethyl amino] -cinnamal-4'- diphenyl-acetophenone,

4- [methylfi-hydroxyethyl) amino] cinnamal-3 '-nitroacetophenone,

4-dimethylamino-cinnamal-3 '-amino-acetophenone,

4- [methyl- ,B-hydroxyethyl amino]-cinnamal-2'-hydroxy-4-dimethylaminoacetophenone,

4,4'-bis'dimethylaminodibenzylidene-acetone,

2,2-bis- (,B-methylamino-ethyl benzal,

pheny1-( l-amino-anthraquinolyl) (2 ketone,

9-hydroxy-4-benzoyl fluorene,

a-anisylidene-u- (3-nitro-cinnamy1idene) acetone,

oc-4- [methylr3-hydr oxyethyl amino] cinnarnylidenea-(4'-ni tnotoluylene)acetone,

4- [methyl- (fi-hydroxyethyl arnino] cinnamal-acetylacenaphthene,

2- [2'- carboxy-monoglycol ester) -benzoy1[-7-diethy1- amino-fluorenone,

1,1-carbonyl-diindazole,

1- 4'-nitrobenzoyl -ind azole,

1 4'-dimethy1 amino-b enzoyl) 6-nitro-indazole,

1- 2'-carb oxyphenyl b enzimidazole,

2- 4"-dimethylamino-benzoyl 3 hydroxy-diphenyl,

2- (4"-dimethylamino-benzoyl) 3 -hydroxy-4-diethylaminodiphenyl,

1- (4'-dimethyl-aminobenzoyl) 3- (4"-dimethylaminophenyl indazole,

1- (4-diethyl-amino-benzoyl 6-nitro-benzimidazole.

(References on following page) References Cited by the Examiner UNITEDSTATES PATENTS Kuehl 9689 Bunge 96-1 Cassiers et a1. 961

FOREIGN PATENTS Australia. Belgium. France. Germany. Germany.

18 4/ 1961 Germany.

OTHER REFERENCES NORMAN G. TORCHIN, Primary Examiner.

10 A. LIBERMAN, C. E. VAN HORN,

Assistant Examiners.

1. AN ELECTROPHOTOGRAPHIC MATERIAL COMPRISING A CARRIER AND AN ELECTROPHOTOGRAPHIC LAYER THEREON, SAID LAYER CONTAINING A LOW MOLECULAR NON-POLYMERIC KETONE OF THE FORMULA
 5. AN ELECTROPHOTOGRAPHIC MATERIAL COMPRISING A CARRIER AND AN ELECTROPHOTOGRAPHIC LAYER THEREON CONTAINING A LOW MOLECULAR WEIGHT NONPOLYMERIC COMPOUND SELECTED FROM THE GROUP CONSISTING OF KETONES AND THIOKETONES HAVING THE FORMULA 